It was not just near the sun, but actually pulling part of the sun out to it...sucking the surface into the cube. This may not be a occupied ship, but actually a massive drone that is the size of Earth itself. I have been carefully monitoring this cube for over 5 years, and was the first to report on it. Its till coming, about every 2-3 months, like its following a cycle or rotation, but then again, there may be thousands of these in our solar system and they may use the solar material to recharge the ship. Also its possible the cube is a space battery of sorts...that recharges with the sun and carries it off to the alien civilization that created it.